[SVGDom] Clipped clipPath support

ClipPaths can be clipped too, e.g.:

  <clipPath id="clip1" clip-path="url(#clip2)">...</clipPath>

Since we're not really drawing clips but resolving their geometry,
asPath() needs to take composed clipping into account (and intersect as
needed).

R=reed@google.com,robertphillips@google.com,stephana@google.com

Change-Id: I25959e22fe50f72042147cfe6b416b6b9ac20cd4
Reviewed-on: https://skia-review.googlesource.com/5720
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Florin Malita <fmalita@chromium.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/experimental/svg/model/SkSVGRenderContext.cpp b/experimental/svg/model/SkSVGRenderContext.cpp
index d8307a05c0..9de605a034 100644
--- a/experimental/svg/model/SkSVGRenderContext.cpp
+++ b/experimental/svg/model/SkSVGRenderContext.cpp
@@ -328,12 +328,20 @@ void SkSVGRenderContext::applyClip(const SkSVGClip& clip) {
 
     const SkPath clipPath = clipNode->asPath(*this);
 
+    // We use the computed clip path in two ways:
+    //
+    //   - apply to the current canvas, for drawing
+    //   - track in the presentation context, for asPath() composition
+    //
+    // TODO: the two uses are exclusive, avoid canvas churn when non needed.
+
     // Only save if needed
     if (fCanvas->getSaveCount() == fCanvasSaveCount) {
         fCanvas->save();
     }
 
     fCanvas->clipPath(clipPath, true);
+    fClipPath.set(clipPath);
 }
 
 const SkPaint* SkSVGRenderContext::fillPaint() const {